1. Field of the Invention
The present invention relates to an agent and method for maintaining freshness in a cut flower over a long period.
2. Description of the Prior Art
It has been considered that shortening of the life of a cut flower is due to reduction of water rising by closure of a duct of a stalk caused by putrefaction of water and also due to discontinuation of supply of nutriments to the flower. As the agent for prolonging the life of a cut flower, there are known (1) a fungicide for preventing putrefaction of water, (2) a saccharide as a nutriment and (3) an agent for preventing evaporation of water from leaves.
Sodium hypochlorite has been generally used as the life-prolonging agent for a cut flower, and sucrose and phosphoric acid have been used nutriments.
As the conventional method for treating a cut flower after harvesting, there has been adopted a method using an aqueous solution containing 8-hydroxyquinoline, aluminum sulfate, STS (a mixture of silver nitrate and sodium thiosulfate) and sucrose.
As other life-prolonging agent for a cut flower, there are known an agent comprising phytic acid (see Japanese Unexamined Patent Publication No, 59-204112), an aqueous solution of hydrogen peroxide (see Japanese Unexamined Patent Publication No. 61-165301), an aqueous solution of sodium thiosulfate (see Japanese Unexamined Patent Publication No. 63-222101) and an aqueous solution containing sodium alginate (see Japanese Unexamined Patent Publication No. 61-165301).
Of the constituents of the life-prolonging agent for a cut flower, sodium hypochlorite (hereinafter referred to as "NaOCl") heretofore used as the fungicide for preventing putrefaction of water alkaline, and therefore, NaOCl is defective in that absorption of water is degraded in a short time.
According to the method for treating a cut flower after harvesting with an aqueous solution of a chemical such as STS, it is still difficult to maintain freshness, that is, fresh color or gloss, and prevent bluing in roses and the like.
Moreover, other known life-prolonging agents cannot show a satisfactory life-prolonging effect in typical cut flowers of chrysanthemum, rose, carnation and white lily.